Baby incubator and the like



June 3, 1941. c. c. cHAPPLE BABY INCUBATOR AND THE LIKE Filed March 4,1938 4 Sheets-Shet 1 WITNESSES: INVENTOR;

Charles (J. Cha Le BY W M ATTORNEYS,

June 3, 1941. c; c. CHAPPLE BABY INCUBATOR AND THE LIKE 4 Sheet-She'et 2Filed March 4, 1938 INVENTOR: Charles (7.0m p12,- BY W ml ATTORNEYS.

j oww c. c; CHAPPLE BABY INCUBATOR AND THE LIKE FiledIMarch 4, 1958FIZGEW June 3, 1941.

4 Sheets-Sheet 3 WITNESSES: Q

wmd

Charles NVENTOR:

ATTORNEYS.

June 3, 1941. c. c. CHAPPLE 2,243,999 BABY INCUBATOR AND THE LIKE FiledMarch 4, 1938 FIG. m

' 4 Sheets-Sheet 4 ATTORNEYS.

Patented June 3, 1941 BABY INCUBATOR AND ma LIKE Charles C. Chapple,Philadelphia, Pa., assignor to The Children's Hospital of Philadelphia,Philadelphia, Pa.,' a corporation of Pennsylvania Application March 4,1938, Serial No. 193,883

9 Claims.

My invention relates to incubators, useful for the prematurely born, orfor infants that are otherwise delicate or sick, or when special careafter birth is desired for any reason. The incubator may also be founduseful for young or sick animals, in some cases.

An important aim of the invention is to isolate the patient in theincubator from all outside influences or infections, and to providedefinite and controllable conditions in the incubator chamber, includingan atmosphere of determinate characteristics, if desired, such as may bemost advisable in each case. Another aim of the invention is to providefor the necessary care, exam-, inations, and treatment of the patient inthe incubator,or for any other attention,-without any interruption orimpairment of the favorable conditions, and without need to withdraw thepatient temporarily for any purpose. Other purposes, features, andadvantages of the invention will appear from the following descriptionof one species or form of embodiment, and from the drawings. All thefeatures and combinations shown or described are, indeed, of myinvention, so far as novel.

Inasmuch as the atmosphere maintained in my incubator may sometimesinclude more (or less) oxygen than ordinary air, or may include carbondioxide or other gas not appreciably present in ordinary air, or mayeven be.entirely artificial or synthetic, .I have hereinafter generallyused the expression respiratory gas," or gas simply, to cover naturalair and all modifications thereof or substitutes therefor.

In the drawings,

Fig. I is a front perspective view of one form of incubator convenientlyembodying the invention, with the front wall closure swung down to openposition, and with a portion of the upper wall and roof structure brokenout.

Fig. II is a rear perspective view of the incubator, with parts oftherear wall broken away or removed. 4 V Fig. III is a partial rearperspective view illustrating the use of certain features of theinvention by a physician, as for examining a baby in the incubator.

Fig. IV is a fragmentary sectional view showing an armlet or sleevedevice attached to the incubator around an arm-port in its wall, butrolled. up and secured or stowed as when not in use; Fig. V is a similarview with the armlet or sleeve device unrolled as for use, the ends ofthe sleeve being partly broken away and in section; and Fig. VI is afragmentary view, partly sectional, showing how a hand is initiallyinserted in the end of the sleeve.

Fig. VII is a somewhat diagrammatic sectional view of the incubatorchamber, equipped with a cooling arrangement for hot weather.

Fig. VIII is a perspective and sectional view of certainapparatus formaintaining the desired atmospheric conditions in the incubator, theview being from the left of Fig. 11. a

Fig. IX is a. wiring diagram illustrating the automatic control andregulation of the atmosphere in the incubator.

In Figs, I and.II, the incubator chamber Ill is shown as a topcompartment in a. cabinet structure H, which also has a lower shelf orvbottom compartment II for accessory equipment. The incubator compartmentIII is completely enclosed, and all its walls (including top or roof I3and bottom It) may be thoroughly thermo-insulated: this is suggestlvelyindicated in Fig. II by a thermoinsulative layer l5 included in the wallthickness. between inner and outer wall shells it and II, which may beof metal or other suitable material. The equipment shelf or compartmenti2 is also shown as enclosed and completely separate from the incubatorcompartment i0, though without any attempt at thermoinsulation.

As shown in Fig. I, the entire front of the incubator chamber I0 isformed by a bottom-edgehinged door l8, which has a lateral gasket l9 tomake a tight joint against arabbetted seat 20 in the edges of the walls,and is provided with swing-fasteners 2| for engaging in sockets 22 inthe walls, behind the seat 20. In Fig. I, the

door I8 is shown swung down to open position,

affording free access for cleaning, sterilizing, or other purposes, aswell as a free view of the interior; and in Fig. II, the rear wall panelof the compartment I 0 has been omitted from its frame 23 (which isremovably secured by screws or bolts 24), and the rear wall of thecompartment I2, has been largely broken away. to reveal the interiors ofcompartments II and I2. Actually, however, the incubator chamber I! canbe kept entirely closed when in use. This is made possible not only byspecial respiratory provisions, but also by the equipment of theincubator chamber l0, including special provisions for the her NIL-whichwould interrupt or impair the favorable conditions, and expose thepatient to infections or drafts.

As shown in Figs. I and II, the equipment in the incubator chamber Iincludes a. metalbasket baby-bed 25, with mattress 26, preferably at thefront of the chamber. There are also precision baby-scales 21,preferably at the rear of the chamber l0, and elevated above the bed 25,as on a pedestal 28, Figs. I, II, III and VII, the pan of the scales 21may serve as an alternative rest for the baby, in lieu of the bed 25, aswhen the latter is being changed. A thermometer 29 is shown mounted onthe rear rail of th bed 25, where it will give porarily not in actualuse; and on the opposite so to speak, in the armports 35, 35,-orotherwise wall, higher above the bed, there is a bracket 32 for holdinga gavage funnel while liquid is administered to the patient therewith.Preferably the shelf 3| and bracket 32 are removable.

roof 13 of the incubator chamber I0, directly over the bed and thedevices 3|, 32, to'givea clear view of the whole interior of thechamber, It is preferably set on a slope of some or less, and may havedouble panes of uninfiamo mable, shatter-proof character, suitablyspaced for thermo-insulation. For illuminating the interior of thechamber I0, an incandescent electric lamp 34 may be conveniently placedtherein,

as in an upper rear corner, with suitable screen- 35 ing to preventglare in the patients eyes.

'I'o permit necessary access to the interior of the incubator chamberIll without opening it, it has wall openings or armports 35, 35,preferably in its front wall 18, with provisions to prevent influx 'or40 efiiux of air or gas when the hands (and arms) of an attendant areinserted through them. For this purpose, flexible tubular armlets or"sleeves 36, 36 of gasproof fabric (e. g., balloon cloth) are attachedto the wall l8 around the openings 35, 35, as shown in Figs. I, II, III,IV and V. ,As shown in Fig. IV, each sleeve 36 has a hoop 311 sewn intothe hem at one (larger) end, which lies in a groove in a clamping ring38 that is secured to the inner side of the wall ID by screws 39. In thewristband hem at the other (smaller) end of the sleeve 36 is enclosed avery extensible elasticirubber) band 40, which gathers or puckers thewristband fabric'together and closes the opening when the sleeve is notin use, This contractile free end of the sleeve 36 fits around anattendants arm above the hand, and the length of the sleeve permits thehand and arm to be introduced into the incubator chamber and movedaround therein freely,,as hereinafter de- 0 scribed.

When an attendant wishes to use one of the sleeves 36, its elastic lreadily allows the wristband to expand .for insertion of a hand, as

shown in Fig. VI. The hand being thus inserted 5 out as it follows thehand through the armport 35, allowing insertion of the arm into thechamber ID to any extent desired. The flexibility and length of thesleeves 36,36 allows the attendant to move his hands and arms aboutfreely in the incubator chamber ID, to do whatever i needed As isapparent from 10 An observation window 33 is provided in the top or 25to or for the patient, as indicated in Fig. III, while all the timeobserving everything in the chamber as he stands in front of it, lookingdown through the window 33. If the attendant wishes, he can readily sliphis hands under a. baby lying on the bed 25 in Fig. III, lift him upwardand rearward, and place him on the scales 21 and weigh him, andafterward return him to the bed again,the range and freedom of movementallowed by the sleeves 36, 36 being ample for this.

When the attendant has done everything desired, he merely draws his armsout through the openings 35, 35 and steps back away from the incubator,thus drawing out and reversing the sleeves 36, 35 through the openings35, 35 and finally withdrawing his hands through the wristbands,whentheir ends are at once automatically closed by the elastics 40, 40, asshown in Fig. V. Then the sleeves 36, 36 may be twisted /2 turn, rolledup, and tucked into themselves,

tend into the chamber 10, preferably in its upper portion at one end,above the'bed 25 and the scales 21, As shown in Figs. I and II,- theinner lock door 34 forms the front lock wall and is hinged to swing openhorizontally, against the end wall of the chamber I0, while the outerdoor is in the top or roof of the air-lock 42 and of the chamber Land ishinged to swing open upward and rearward, Fig. II. Internally, the

bottom of the lock-chamber 42 is shown stepped,

affording convenient places for anumber of tall milk bottles, and forshorter articles. With the lock 32 in the location shown, its inner door44 and its interior are readily accessible to an at-- tendants hand wheninserted through one of the sleeves 36, as he stands in front of theincubator in Fig. III; and the outer lock door 45 is also within easyreach'oi' his (other) hand, Moreover, the lock chamber 42 serves as ascreen or shield to keep the light 34 from shining in the patients eyes.Very small articles can either be passed in and out through the lock 42,Or introduced and withdrawn in the hand, through one of the sleeves 35.

As shown in Figs. III and VII, an apertured plug-in fitting is providedin the top or roof of the incubator chamber l0, consisting of an elasticvulcanized rubber stopper 4'! with a hole through it. This device allowstubular connections to be made therethrough from the baby to a pointoutside the chamber roof, adjacent the attendants head as he stands atthe window 33.

For this purpose, one or more metal or other tubes 48 may be inserted inthe rubber stopper 41, from the inside or the outside, or both, andrubber tubing may be attached thereto inside the chamber I0, and alsooutside if required. By means of such tubular connections, manyoperations can be conveniently eifected,such as administration ofemergency oxygen and carbon dioxide, aspiration, or stethoscopicexamination as shown in Fig. III, etc. Asis apparent from Fig.

III, such tubular connections, do not interfere 7 2,248,999 with theattendants view through the window asas he stands with hishand (s)inserted through the sleeve (s) 36.

Complete isolation of the patient in the closed incubator chamber In isin itself a very helpful protection againstinfection, as well asagainst- The operation of the heater 49 may be automati cally controlledand regulated by a thermostatic device located at a suitable point inthe chamber 19, so as-to respond to the atmospheric temperatureaffecting the patient. As shown in Figs. I and II, the thermostat 5| ismounted on the end wall of the chamber l6 beneath the air lock 42, butwell above the bed 25, alongside a protective foraminous metal grillage'5! sur-- rounding the open discharge end of the air supply conduit 59and the air heater 49,said heater 49 being in this instance locatedwithin the chamber 19 itself, and wound on or around the upper end ofthe conduit 59. The thermostat 5| and the heater 49 serve to maintain asubstantially constant and uniform temperature in the incubator chamberl0, regardless of outside vari ations.

temperature desired from time to time.

In the case of the prematurely born, fairly high temperatures aredesirable for the air breathed, as well as for the general environment:e. g., some 85-90 F., for example. The isolation of the incubatorchamber II and the effective control and uniformity of the temperaturetherein afford the further advantage that clothing can be graduallyreduced, and even discarded altogether after a baby has becomeaccustomed to the incubator: e. g., a shirt and diaper are quitesuflicient clothing. This not only simplifies the care of the babywithoutopening the incubator, and facilitates examining him in any andevery way, but allows him freedom of exercise, as well as skinventilation.

Besides temperature, another condition or Located as shown, thethermostat 5| is easily reached through one of the sleeves 35, for thepurpose of setting it to maintain the exact ings of the pipes 50, 54)downward (about 2 ft.)

characteristic of incubator atmosphere which it is highly desirable tocontrol and regulate-is the humidity; and as the most advantageous wayof doing this, I provide for humidii'ying the air or respiratory gassupplied to thechamber ll, preferably under the automatic control of ahumidostatic device 53 suitably located in the chamber to respond to thehumidity there. As

mounted on the end wall of the chamber ll adiacent the thermostat 6|,well above the bed 26. It is also desirable to purify the respiratorygas As shown in Fig. II, the gas supply pipe 50 already mentionedextends from the incubator chamber l0 downinto the lower compartment II,where the treating and circulating equipment of the system is located,as well as some of the control provisions. For withdrawing the air orgas from the chamber l0, an outlet or return conduit 54 extends from thechamber l0 down into the compartment l2. The return conduit 54 may be atthe same end of chamber I'll as the supply conduit 50, but its openingis preferably at a lower level than that of conduit 50, though higherthan bed 25. The air or gas supplied through conduit 69 rises throughthe heater 49 at once to the top of the chamber l6 and flows to theother end thereof, where it descends and returns to conduit 54, byreason of the suction therethrough, all as shown by the arrows in Fig.II. Some silk threads 55 hanging in the upper left hand corner ofchamber Ill, over supply pipe 50, show when the circulation is workingproperly. Thus the circulation in the chamber I0 is substantially ormainly confined to its upper portion, above the bed 25, leaving thepatient on the bed out of the principal path of air flow. As shown, theopen upper end of conduit 54 is cut oil diagonally, to minimize thepossibility ofblockage by accidental coverage of thesame. At theopposite end of the chamber l0, preferably, from the supply and outletconduits 50, 54, there is a Pressure-relieving air or gas vent pipe 55,extending from the chamber bottom l4 (below the openthrough thecompartment I2 and beneath the floor of the latter, where its end isopen. A foraminous tubular hood or screen 56 is shown over the openupper end of this pipe 55, to prevent dirt or lint from getting into itand clogging it up. The temperature in the closed chamber In makesinflow of air through pipe 55 impossible, being normally higher than theoutside temperature. The fact that the vent pipe 55 opens from thechamber bottom below the path of circulation therein assures gradualremoval and replacement of the stagnant air in the bottom of thechamber.

The circulating and conditioning equipment in compartment 12 includes(Figs. II and VIII) a receiving, mixing, and filtering chamber in acasing 66; a (centrifugal) blower 6|, directly driven by an (electric)motor 62, and preferably of a silent type; and a humidifier in a tank orshown in Figs. I and II, the humldostat 59 is casing 63, which may serveto wash the air or respiratory gas more or less. ,Into one end of thechamber 69 are connected the return condult 54 from the incubatorchamber l9 and a valved supply fitting 64, serving forthe attach ment ofa flexible hose leading out of doors, or to any suitable source of pure,fresh air. Another valved supply fitting 66 is shown connected into thesame end of the chamber 60,for

' the attachment of a hose connection (not shown) supplied to thechamber II by filtering or other means, so as to exclude dust and dirtfrom the chamber. To facilitate the humidifying, heating pensativelyventing air or gas from the system,

to relieve the pressure that would otherwise tend tobuild up in thechamber ll.

admitting oxygen or other respiratory gas which it may be desired to mixwith that returning through the conduit 54. Into the opposite end of thechamber 60 is connected the (axial) intake of the (centrifugal) blower6|, whose (peripheral) discharge delivers into the upper part of theclosed casing or tank of the humidifier 63 at one end. A valve-cock 68is shown on the blower casing, for taking samples ofthe incubatoratmospherefor test or analysis. At an intermediate point between theconnections 54, 64', and 66 and the blower 6|, one or more air or gasfiltering diaphragms 69 extend entirely across the interior of thechamber 60. As indicated in Fig. VIII, one side III of the chamber orcasing 60 is readily removable, to allow inspection or renewal of thefilters 69.

As shown in Fig. VIII, a valved exhaust line H (leading out of doors)may be-connected to the return conduit 54, with suitable dampers orvalves, to allow of exhausting the gas from the chamber In, instead ofrecirculating it.

As shown in Figs. II and VIII, the air or gas supply conduit 50isconnected into the upper portion of the humidifier tank 63 at theopposite end from the blower 6|, so that the air or gas from the blowerpasses through the tank from end to end, in contact with the body ofwater in its lower portion. If desired, one or more baflles l2, -'l2 mayextend down from the tank top close to the surface of the water,'and mayeven dip into the water, if its level is higher than shown in Fig.III,--to compel intimate contact of the air or gas with the water, so asto be cleansed or washed thereby. Immersed in the water in thehumidifier tank 53 is shown an (electric) heater [3 for heating andvaporizing the water,and even boiling it vigorously, if need be,so as tohumidify the air to any degree desired, up to complete saturation.Obviously, the control and regulation of this heater 13 by thehumidostat 53 will determine the percentage humidity in the chamber lii.

To assure a substantially constant'surface exposure of water to the airin the humidifier 63, it suffices to maintain a substantially constantamountand level of the water. As one way of doing this, water may besupplied to the humidifier tank through a pipe connection 15 from asupply apparatus 16 (resembling a common form of water cooler)comprising a vessel in whose open top sits an inverted bottle 11, sothat the level in the tank corresponds to the vertical position of thebottle-mouth. Distilled or boiled water is to be preferred for thehumidifier 63.

As shown in Fig. II, the compartment I2 contains a control-panel 18carrying various electrical parts and mechanisms, hereinafter set forth.There is also an electric lam'p 19 mounted on the floor of thecompartment l2, in position to facilitate inspection of the water supplyat H, the control-panel I8, or the filter 63, as well as the making ofhose connections to the fittings 64, 66, or the adjustment of theirvalves to regulate the supplies of air or gas through them. v

In hot weather, cooling rather than heating may be required to maintaindesired living temperatures of the respiratory-gas in the incubatorchamber Hi. This may be effected anywhere in the circulatory system ofthe incubator; and one simple way is to do it in the chamber Ill itself.For this purpose, Fig. VII shows the chamber ID with its usual(thermoinsulative) rear wall panel and its frame 23 removed, andreplaced by a cooling wall 301 attached to the incubator by the screws24 that usually serve to secure the panel frame. As shown, this wall 80comprises a (thermo-insulated) metal tank with a hinged lid 82, whichmay contain any suitable cooling medium, such as a body of water, brine,or other liquid, itself kept cool (for example) by pieces 83 of ordinaryice (or dry ice) immersed in the liquid. The cooling effect may beaugmented by providing the cooling wall 80 with heat-absorbing meansprojecting into the chamber Iii, such for example as metal tubes 85having their upper and lower ends secured in the tank wall, so that thecooling liquid in the tank may circulate through them.

Whatever its character and'arrangement, the cooling means employedshould, of course, be capable of cooling-the respiratory gassufficiently to maintain the desired living temperature in the chamberl0 under all c0nditions,even

.when the external temperature reaches the extreme possible limit ofexcess. When this is thecase, variations of the excessive externaltemperature will always be compensated for automatically by the heater49 and the thermostat 5|: e. g., if the wall tends to overcooi theatmosphere in the chamber In, the heater 49 will operate enough tomaintain the desired constant temperature there, notwithstanding anyvariations of the excessive external temperature-just as if the entiresurroundings of the incubator were over-cool, rather than overhot.

Fig. IX illustrates one suitable scheme of electrical connections forthe incubator, whose main operating electric circuit 99 may be suppliedwith current (through a flexible cord, not shown) from any suitable A.C. or D. C. source,- such as an.ordinary 110-120 volt house lightingcircuit (not shown).

As shown in Fig. IX, the main operating circuit is connected to theaforesaid flexible cord (not shown) through a normally closed controlswitch 9|, located in any convenient position on the incubator cabinetDirectly across the main incubator circuit 90 are connected the lamps 34and i9 and the motor 62 that drives the blower 5| so that circulation ofrespiratory gas through the incubator chamber I0 is assured whenevercurrent is on, and any failure of current supply is obvious at a glance.In parallel across the main circuit 90 are connected supply circuits 92,93, for the respiratory gas heater 49 and the humidifier water heater13, controlled by thermostat 5| and humidostat 53, respectively. Asshown, the circuits 92, 93'include relay switches 94, 95 which closewhen their operating coils are energized from control circuits 96, 91that are connected across the supply circuits 92, 93, and includethermostat 5| and humidostat 53, besides current-limiting resistances98, 99. Thermostat 5| and humidostat 53 maybe of any commercial typesthat will open the circuits 96, 91 when the temperature and humidityrise to the limits for which they are set, and vice-versa. By reachingthrough a sleeve 35, they may be set and reset to maintain anytemperature and percentage humidity that may be desired from time totime, within a range of deviation not exceeding 1' F. and 5% ofsaturation.

As a protection against any possible failure of the switches 94, 95 toopen when required, or

against excessive temperature in the incubator chamber l0 arising fromany cause, a safety thermostatic device Hill is shown in Figs.- I andII, (and IX), inounted'on the end wall of the chamber between thermostat5| and humidostat mostat I99 is itself in a control circuit )2 connectedacross the main circuit 90 and including the operating coil of relayswitch llll, as well as a current-limiting resistance I03. Analarmcircuit I04 is shown connected across the main circuit 90, andincluding an audible alarm bell I05 and a (red) light I 06-connected inparallel therein, as well as contact l0! arranged to be closed by therelay switch llll when it drops open, and a control switch I08 of itsown. The safety thermostat I00 may be of any commercial type thatoperates to openits circuit I02 when the temperature-rises to the limitfor which it is set, and (preferably) requires to be manually closedafter each operation. Or, if preferred, the relay switch IDI may be suchas to require manual resetting aiter each operation.

' The dot-and-dash outline of the control panel 18 in Fig. IX includesthose features of the electrical system which may ordinarily be mountedon this panel in practice.

The use and operation of the incubator and its circulating andconditioning system will for the most part be apparent from what'hasalready been said. Aided by cooling from a wall tank 80 in hot weather,the system is capable of automatically maintaining in the chamber iii anatmosphere whose essential characteristics of temperature and humidityare definitely determined and kept constant-,-its purity being assuredby filtering and by admixture of outside The fresh air or therecirculated air (or both) may be exposed to ultra-violet light tosterilize the air completely. The exact composition of the incubatoratmosphere can be con-' trolled as desired by supplying oxygen or other"gas at 66 and by suitably adjusting the valves at 64, 66. If desired,valve 64 can be closed, and the whole system (including chamber Ill) maybe charged and operated exclusively with special mixtures of gases,supplied for replenishment at 66. Or, by closing both the valves at 64,56, the gas in the system may be recirculated indefinitely, withoutsubstantial addition or loss. Under these circumstances, chemicals forabsorbing carbon dioxide, odors, or excess water vapor may be introducedinto the circulatory system where most convenient.

Having thus described my invention, Iclaim:

1. The combination of a closed incubator chamber, with a transparentwindow at its front, for containing an atmosphere of respiratory gas ofdeterminate characteristics, to be breathed bya patient in the chamber;a rest and weighing scales for the patient in the lower part of thechamber, beneath said window; and flexible sleeves attached to the frontchamber wall around arm openings therein and permitting an attendant toinsert his hands into the chamber and said sleeve, and including meansfor excluding from the lock the respiratory gas and the outside air.

3. In an incubator of the character -described, the combination of aclosed incubator chamber, with a transparent window at its front, forcontaining an atmosphere of respiratory gas of determinatecharacteristics to be breathed by an infant in the chamber; flexiblesleeves attached to the front chamber wall around arm openings thereinand permitting an attendant to insert his hands into the chamber andmove them around therein; and an air lock for passing articles into andout of theincubator chamber comprising a lock chamber in one end of theincubator chamber, accessible to an attendants hand inserted into theincubator chamber through one of said sleeves, with an inside closurefor excluding respiratory gas from the lock chamber, and an outsideclosure for excluding outside air therefrom located within reach of ahand of the attendant while observing the infant through the window andreaching the air lock witl. his other hand inserted through one of saidsleeves.

4. In an incubator of the character described, the combination of aclosed incubator chamber, with a transparent window at its front, forcontaining an atmosphere of respiratory gas of determinatecharacteristics to be breathed by an infant in the chamber; a bed in thelower front part of the chamber, beneath said window; weighing scalesinthe chamber, behind said bed; and flexible sleeves attached to the frontchamber wall around arm openings therein and permitting an attendant toinsert his hands into the chamber and move them around therein, so as toattend to an infant on the bed while observing him through the window,and to shift the infant from the bed to the scales and weigh him on thelatter, all without substantial influx or escape of air or gas.

5. In an incubator of the character described, the combination of a.closed incubator chamber, for containing therein an atmosphere ofrespiratory gas of determinate characteristics to be for excluding therespiratory gas from the lock move them around therein, so as to attendto a patient on the bed while observing him through the window, and toweigh him on the scales, all

around an arm opening therein for permitting the hand and arm of anattendant to be inserted into the incubator chamber and moved abouttherein without material influx or escape of air or gas; and an air lockfor passing articles into the incubator chamber into reach of theattendant's hand inserted into the chamber through chamber and a closurefor excluding therefrom the outside air.

6. In an incubator of the character described,

the combination of a closed incubator chamber,

and means for circulating respiratory gas therethrough; a humidifier anda heater for-the gas thus supplied to said chamber, both including meanswhereby heat is supplied to the gas; an electric circuit iorsupplyingenerg'y to activate said circulating means, said humidifier,and said gas heater;. means responsive to the humidity and thetemperature in said chamber for controlling the activation 01' saidhumidifier and said gas heater from said electric circuit, withoutaffecting that of said circulating means; and

means independently responsive to excessive temperature in said chamberfor cutting 011 both said humidifier and said gas heater from saidcircuit, while leaving said circulating means connected thereto.

7. In an incubator of the character described, the combination of aclosed incubator chamber, and means for circulating respiratorygas-therethrough; a, humidifier for the gas thus supplied to saidchamber, with means for heating and vaporizing water therefor; a heaterfor heating said gas; means responsive to the humidity and temperaturein said chamber for controlling the heating of the water and the gas,respectively, by the corresponding means aforesaid, without afiectlngthe operation of said gas circulating means; and means independentlyresponsive to excessive temperature in said chamber for rendering bothsaid water heating means and said gas heater inactive, also withoutaffecting the operation of said gas circulating means.

8. An incubator oi the character described comprising a unitaryuprightcabinet with an impermeable dividing floor defining in the cabinet asubstantially closed upper incubator compartment and a separate lowermachinery compartment; 9. bed on said floor, in the lower portion ofsaid upper compartment; conditioning means in said lower compartment,including a gas-humidifier; a gas-supply conduit extending from saidlower compartment up into said upper compartment, and discharging in itsupper portion, substantially above a patient on the bed, and a returnconduit drawing from a level in said upper compartment substantiallyabove a patient on the bed and extending down into said lowercompartment, so that the patient on the bed is left clear of any draftdue to the circulation, and mechanical air circulating means in saidlower compartment, beneath said floor, for drawing respiratory gas fromsaid incubator compartment down through said return conduit and passingit through said humidifier and back through said gas-supply conduit intosaid incubator chamber.

9. In an incubator of the character described,

1 the combination of an incubator chamber:

therein, even when the external temperature is excessive; so that by thecooperation of said heating and regulating means with said coolingmeans, a substantially constant desired temperature and humidity may bemaintained in the chamber, notwithstanding variations of the excessiveexternal temperature.

I CHARLES C. CHAPPLE.

